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NEED HELP! - streaming text for cgi web chat

Posted on 1997-07-17
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Last Modified: 2008-03-17
Ok, PERL gurus! I am working on a project to allow streaming(scrolling) text for a cgi chat server in a
multi-framed HTML document. I have seen several client / server models and sample code, but cannot seem to get it straight. The problem I see with many of the
sample daemons is that they create way too much server
load. ex. The have to spawn a child process to
communicate with a newly opened socket. I need a
server to accept incoming sockets and to print messages
recieved from a socket to all other open connections
from ONE process(I guess this would be similar to the
innd process). I will be INCREDIBLY grateful for some
advice as this is an extremely important feature for me to
add. Thank you very much.


------ Text Omitted .... Code needing fixed is listed below


I feel the code is almost there, but it has bugs in it. I've set the server to listen on a particular port. Rather then writing the client, I've just telneted in to test the
response. Once the socket is opened, I type in data(then of course the steam will be ended via a \n) and the data is sent back to my socket and it is then closed. For some
reason the text is not being broadcasted to other open connections. I'd really appreciate further help if it is possible. Also, once completed this version should be
able to support up to and even beyond 50 - 100 simultaneous users. Is this feasable with this implementation. Here is my code so far. Also The cgi web-based interface will be in a
3 frame window.  The upper left frame will recieve all new
text written by other chatters.  The lower frame will allow the user to add new text, which will in turn be sent to the upper right frame.  The third frame will be used for customizable options.
Thank you greatly! - Eric

               #!/usr/bin/perl
                 
               ($port) = @ARGV;
               $port = 2345 unless $port;
                 
               $AF_INET = 2;
               $SOCK_STREAM = 1;
                 
               $sockaddr = 'S n a4 x8';
                 
               ($name, $aliases, $proto) = getprotobyname('tcp');
               if ($port !~ /^\d+$/) {
                   ($name, $aliases, $port) = getservbyport($port, 'tcp');
               }
                 
               print "Port = $port\n";
               $this = pack($sockaddr, $AF_INET, $port, "\0\0\0\0");
                 
               socket(LISTEN, $AF_INET, $SOCK_STREAM, $proto) || die "socket: $!";
               bind(LISTEN,$this) || die "bind: $!";
               listen(LISTEN,5) || die "connect: $!";
                 
               select(LISTEN); $| = 1; select(stdout);
                 
               print "Listening for connections....\n";
                 
               while (1) {
                   # each time, create the select bit array
                   $bits = 0;
                   for (@CLIENTS) {
                   vec ($bits, fileno ($_), 1) = 1;
                   }
                   vec ($bits, fileno (LISTEN), 1) = 1;
                 
                   #OK, wait until something comes in.
                   $nfound = select($rbits=$bits,undef,$ebits=$bits,undef);
                 
                   #OK, something woke us up.
                   # see if it is a new connection...
                   if (vec($rbits, fileno(LISTEN), 1)) {
                   # new connection
                   accept (NS, LISTEN);
                   push (@CLIENTS, NS); }
                 
                   #no, try the clients
                   $incoming = undef;
                   for (@CLIENTS) {
                   if (vec ($rbits, fileno ($_), 1)) {
                   #OK, this client's got something, read a line...
                   $incoming .= <$_>; } }
                 
                   # next, send $incoming to all clients...
                   if ($incoming) {
                   for (@CLIENTS) {
                   print $_ "$incoming\n"; } }
                   }
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Question by:knight76
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2 Comments
 
LVL 84

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by:ozo
ID: 1204925
Using the -w flag says:
Unquoted string "stdout" may clash with future reserved word at line 24.
Name "main::ebits" used only once: possible typo at line 37.
Name "main::NS" used only once: possible typo at line 43.
Name "main::nfound" used only once: possible typo at line 37.

 
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LVL 84

Accepted Solution

by:
ozo earned 90 total points
ID: 1204926
Perhaps more tellingly,
use strict;
gives the error
Bareword "NS" not allowed while "strict subs" in use at line 45.

Could it be that
      push (@CLIENTS, *NS);
was what you meant?

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